Re: CIFS - VFS error question

[Jeff Layton <jlayton-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

On Thu, 27 Sep 2012 09:37:09 +0100
Sachin Prabhu <sprabhu-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> wrote:

> On Wed, 2012-09-26 at 09:33 +0200, ROBIN CERNIN wrote:
> > Hello,
> > 
> > First of all I wanna say you are doing great job developing cif-utils.
> > Secondly I have question on using following version of cifs:
> > 
> > filename:       /lib/modules/2.6.18-308.8.1.
> > el5/kernel/fs/cifs/cifs.ko
> > version:        1.60RH
> > description:    VFS to access servers complying with the SNIA CIFS
> > Specification e.g. Samba and Windows
> > license:        GPL
> > author:         Steve French <sfrench-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>
> > srcversion:     63D9396D38F380652744D7E
> > depends:
> > vermagic:       2.6.18-308.8.1.el5 SMP mod_unload gcc-4.1
> > parm:           CIFSMaxBufSize:Network buffer size (not including
> > header). Default: 16384 Range: 8192 to 130048 (int)
> > parm:           cifs_min_rcv:Network buffers in pool. Default: 4
> > Range: 1 to 64 (int)
> > parm:           cifs_min_small:Small network buffers in pool. Default:
> > 30 Range: 2 to 256 (int)
> > parm:           cifs_max_pending:Simultaneous requests to server.
> > Default: 50 Range: 2 to 256 (int)
> > module_sig:    883f3504fa440f6a462ac2afa8e12f112b2f409f6ea4176acbbe7f2f2c13e944e9a17d507b429c09c8e9ef6118eb3d5c40fcbfa81c96bf86e626c06e
> > 
> > on RHEL get following errors in the /var/log/messages:
> > 
> > Sep 24 20:08:48 xxxxxxx kernel:  CIFS VFS: No response for cmd 50 mid 39222
> > Sep 24 20:08:48 xxxxxxx kernel:  CIFS VFS: No response for cmd 50 mid 39231
> > Sep 24 20:08:48 xxxxxxx kernel:  CIFS VFS: No response for cmd 50 mid 39236
> > Sep 25 10:45:16 xxxxxxx kernel:  CIFS VFS: Send error in SessSetup = -5
> > Sep 25 10:45:16 xxxxxxx kernel:  CIFS VFS: Unexpected lookup error -5
> > Sep 25 13:08:25 xxxxxxx kernel:  CIFS VFS: No response for cmd 6 mid 47208
> > Sep 25 16:50:27 xxxxxxx kernel:  CIFS VFS: No response for cmd 162 mid 48857
> > Sep 25 20:07:37 xxxxxxx kernel:  CIFS VFS: No response for cmd 50 mid 50442
> > 

As Steve pointed out the above indicates a lot of timed-out requests.
The EIO errors however are somewhat troubling. It's not clear what
would have caused that...

> > 
> > Can you please clarify a bit to me what are these errors related to? I
> > dont hear anyone complaing that this isnt working but I can still see
> > these errors.
> Hi Robin, 
> 
> Did you have any network outages or network congestion at those times?
> It appears the client for some reason couldn't receive a response from
> the server.
> 
> Sachin Prabhu
> 

It's not uncommon for windows servers to take a long time to respond to
certain types of requests. For instance, writes that are long past the
EOF can take *minutes*. NTFS doesn't do sparse files efficiently and
has to zero-fill the gaps before it replies.

More recent kernels (including RHEL6) implement a different mechanism
for timing out requests that's more resilient in the face of this sort
of server behavior. RHEL5 however is approaching its end of life, and
backporting something that invasive is probably a non-starter.

If you have a RH support contract, you may want to open a case so we
can help you do some better diagnosis.

-- 
Jeff Layton <jlayton-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>